Self-assembled systems can feasibly be very small (several atoms), a la DNA (a natural self-assembling system). Lithographic systems (electron beam or optical) are limited by diffraction of the corresponding electrons or photons used to expose the photoresist, as well as the surface properties of the photoresist itself. For these methods the minimum feature size producable can be of order 10 nm for e-beam lithography, and 100 to 1000 nm for optical lithography, depending on wavelength. Self-assembled systems could possibly be as small as order 1 nm in size.
Is this (programmable matter via quantum wells/dots) something that actual work is being done on anywhere, or that actual signs of progress can be seen in, or that Mr. McCarthy has the actual capacity to encourage actual science work to be done on?
First a note - All of my experience with quantum dots is at cryogenic temperatures, eg 4.2K and below, so I'm not aware of the behavior of systems at higher temperatures.
It sounds like this author is making very generalized hand-waving explanations about these fairly complex systems. And is vague enough so that if any effect is discovered, he'll claim that he "discovered" it first. But if he did claim that, it would be somewhat disingenuous because it's very difficult to predict what kind of coherent long-range many-body "emergent" patterns would manifest themselves. Ie, the low-level physics is hard, the fabrication is hard, determining large-scale effects is hard, etc. Heck, even describing a simple helium-atom is hard enough (the quantum-mechanical 3-body problem), with three interacting coulomb forces to work with in addition to the nuclear potential. So it sounds like he's handwaving, but in an attempt to claim prediction of any future discovery based on quantum-dots.
On a side note, though, all matter is already programmable by default. Phase transitions, for example, will happen at specific temperatures, or magnetic fields, etc, such that the macroscopic behavior of the material can be 'programmed' by pushing through the phase transition.
That is, using quantum stuff as a new mechanics for our current paradigm, instead of coming up with a new paradigm that actually utilizes quantum properties fully.
That pretty much is what researchers in quantum computing are trying to do, it's a whole different ballgame. For example, In classical computing, 3 bits lets you put a system into exactly one of 8 (2^3) distinct states. However a quantum computer with 3 qubits will let you put the system into a superposition of these eight states, such that the superpositiong (ie, wavefunction) is properly normalized.
Quantum mechanics works in a whole different mathematical basis (Hilbert Space or Fock Space). The algebras of these spaces is quite different from classical computing, so yes, it's going to be a whole new way of looking at computing, at least at the lowest level.
On a side note, it sounds like you have just read some Thomas Kuhn, as per your frequent usage of 'paradigm', along with comparing 'evolution' to 'revolution'.
Yeah, I was just giving a rough semi-relevent response to show that He3 does indeed have uses here on Earth. But of course whether it's actually efficient to mine it on the moon and transport back to Earth, and if the cryogenics community is really large enough to justify that, is a whole different matter, which I cannot answer.
But hey, I was fiddling with a He3 fridge as you wrote that, so I had to give at least some response!
I don't really understand what you're asking, but I gave a semi tongue-in-cheek response to the parent poster (probably not too noticeable). Meaning that I only argued against the fact that He3 has no use on Earth, but of course not implying it would be efficient to mine He3 on the moon.
They'll do a trial collection of Helium 3, but there won't be any point, because there's no use for Helium 3, even if we could get it back to Earth.
Interesting comment, I use He3 (in closed systems) almost every day in my lab. He4 liquefies at 4.2K, but that's a bit too toasty for probing certain quantum coherence interactions and quantum phase transitions. A liter of liquid He4 costs about $4 (liquid nitrogen, at 77K, is cheaper than milk). But a gaseous liter of He3 is several hundred dollars.
We've got a sorption-pumped He3 refrigeration system that uses a closed-cycle He3 unit for evaporative cooling, and the whole things sits in a dewar of He4 at 4.2K. Can get to temperatures of about 250 mK.
When we need to go colder we employ a dilution refridgerator, which uses a carefully-tuned mixture of He3/He4, and can create a phase separation between a dilute and condensed mixture of the two helium isotopes. By crossing the phase boundary from the condensed to dilute phase, one can absorb heat from a sample (very similar to standard air conditioner cycling). We can get down to about 10 mK with this system, but it'll take you all day and lots of prep work to just to load and cool one sample.
So yeah, the cryogenics community would love getting more He3. It's really rare here on Earth, but it would be really cool to have more of this stuff. I don't know what other industries would make use of it, but it would probably find other useful applications.
Studies are the way to get funding for experiments, which get things like this started.
You've got the most limited worldview of scientific research I've ever encountered. Theoretical research is done all the time to further our knowledge. What kind of scientific research do you do that gives you authority to make this comment?
Many times the end results cannot be determined to have any practical usefulness, but it builds on the world body of knowledge that can be eventually used. For example, think of the first researchers studying band structure of doped silicon. Sounds pretty boring, but it's the cornerstone for the entire microelectronics industry. It took scientists with clever insight to be able to apply this research to make PN junctions, and then transistors.
But where does this mean they will carry it forward? For example, various biologists study complex predator-prey relations, and can determine situations where the tigers kill all the gazelles on the land very quickly, extincting first the gazelles and then themselves. Do you actually think they then seek funding to try to instantiate this model? If it was something smaller-scale, such as two bacteria species in a jar, then perhaps a researcher would try to verify the model. But they don't do it just to get funding, as you say.
Responsible climatologists are putting their time and effort into helping to understand the mess we're making on Earth, before spreading it to Mars.
First of all she's a planetary scientist, and an undergrad student to boot. Secondly, this climactic study was most likely spun off from similar research on PFC's or other fluorocarbons here on Earth. Thirdly, whatever results they get from this study have a decent probability of adding to the body of knowledge for Earth-based climatologists studying various global warming scenarios.
For example, one difference between Earth and Mars warming is that Earth has a much larger ozone layer, which is affected by CFCs. That's why PFC's are looked at in the Martian study instead, and also they're looking at possible methods that might create a larger Martian ozone layer. Such research could help terrestrial scientists if it's determined that our ozone layer needs to be repaired.
I guess NASA's scienticians have determined there is no life on Mars then?
What are you talking about? Can you point to any links that document real PROPOSALS by "NASA scienticians" to actually warm Mars (as opposed to mere studies and models)?
Or are you knee-jerking based on the misleading slashdot summary that implies there really is such a proposal?
It's ironic that you want to belittle "NASA scienticians" for arriving at premature conclusions, when you yourself have done the exact same thing by not even spending 30 seconds to click on a link and read the article.
Is now a good time to tinker with another planet's atmosphere?
If you actually read the article, and not just the misleading sensationalist slashdot blurb, you'd see this is not a PROPOSAL to heat Mars. It's a STUDY to look at various options that COULD be used to terraform Mars, and how to get past various other problems that would crop up (for example relying exlusively on CO2 for the warming process).
And either way, these studies are either spinoffs of, or will contribute to, studies of Earth-based global warming, and can help provide useful data and methods for understanding these problems close to home.
Well, you do not know if there's life unless and until you do research. What if you jump the gun and change Mars before you complete all research?
Did you at least read the article? The slashdot writeup was sensationally misleading, as usual. Actually, here's some more info on the project, more than is in the Guardian link.
Basically, it is NOT a proposal to warm Mars, it's a study exploring various ways that Mars COULD be heated, and how long such methods would take (conducted by an undergrad student at U. Mass). And they even acknowledge in that link that it would be significantly well into the future before any decision would every be implemented to try warming Mars, and at that point the method of using PFC's would probably be archaic compared to future technology.
So keep your pantyhose on, NASA isn't trying to warm Mars, it's just a study. And in all likelihood it was an offshoot of various studies of global warming on Earth, in which case doing more planetary models of effects of PFCs, among others, would be a good thing!
Re:um, car's aren't rockets...
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Hondas in Space
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· Score: 1
NASA, whose rockets blow up when they launch in cold weather?
You mean, NASA, who's bureaucratic administrators pushed for the launch (with I believe governmental pressure), against the objection of the engineers familiar with the system that failed. Don't dis all of NASA's engineering abilities and accomplishments because of PHB's and politicians.
NASA, whose craft break up on re-entry just because they got smacked with some foam?
Your statement here is so deceiving, I really hope you don't believe it yourself. It wasn't foam that broke up the craft, it was the friction heating on re-entry. And that happened because the heat shield was damaged by a piece of 'foam', but the foam didn't directly break up the shuttle.
But thanks, because your example proves the point of the poster. Shit happens, and NASA has many redundancies to deal with said shit happening. Spacecraft are far more complex than mere cars, so in space shit happens greatly. You need to be far more familiar with aerodynamics, materials stress and thermal properties, reactive propulsion, than the standard automobile hacker needs to be.
What evidence do you have that NASA is better at this than anybody else?
They're not necessarily, but I think the poster meant Aerospace professionals, not just Joe Hacker Schmoe who can soup up his Honda Civic. For example, much rocketry and other components come from Boeing and Lockheed-Martin, among other subcontractors.
But there's SO MUCH MORE that can go wrong with space systems, as opposed to autos, and when stuff goes wrong in space it tends to go REALLY wrong. Eg, an out of control car can steer towards some bushes to slow down, but an out of control orbiter during re-entry is pretty fucked.
The software DOES matter. Tell that to my friends and former team-mates at NASA IV&V who found a number of errors, several of them mission critical.
Of course the software matters, what doesn't matter is that the software is 20 years old (as long as it processes/transmits data fast enough, which it does). Bugs are bugs, but age in itself doesn't make software bad. In fact, one could claim that older software has had more exposure time, allowing the identification and debugging of more mission-critical bugs.
BTW, my girlfriend works at STScI, so I know a few things about HST;-)
Re:Question for you astronomers out there....
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A Star of Space and Film
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· Score: 2, Interesting
The hubble is a digital camera but not like the type you have at home. The WFC3 (wide field planetary camera version 3) or the COS (Cosmic Origins Spectrograph) take the images.
WFC3 and COS are still on the ground, hopefully to make it to Hubble on either a manned or robotic mission. Here's a list of past, present, and future Hubble instruments, along with links to their homepages with all the technical information you could want.
Hubble is nowhere near state of the art (some software in it is 25-30 yrs old) but it works and has exceeded the wildest expectations of it's builders. Kind of a Brooklyn Bridge in space, the first one built but still works great and setting a high standard.
The software doesn't matter, it's the front-end detectors that limit the accuracy on the acquired data. Once it's properly digitized, the software will only limit the speed it can be transmitted back to Earth. But even that speed is dwarfed by the long integration times Hubble acquires for very faint objects.
The accessibity of Hubble is what contributed to it's success. Sensor technology is a continuing evolving field, and the ability to periodically put better, more sensitive detectors onto Hubble has contributed to it remaining one of the most competitive telescopes available. When James Webb telescope is launched, it won't be upgradeable, which means it won't be able to take advantage of the great advances in sensor technology we'll probably have in the next 20 years.
More power means more oil and its associated problems like the greenhouse effect, wars, polution, poverty, etc. Isn't it just counterproductive to use more oil and produce more toxic waste that escapes to the atmosphere forever in order to solve a problem of a "waste" in the form of self-contained expensive hardware which can always find a second-hand market in the developing areas?
Okay, I'll bite. Did you read the article, or are you just knee-jerking?
You've listed one or two problems with recycling, but haven't identified related problems with NOT recycling, nor have you considered of the appropriate scenarios which approach would have the most beneficial impact on the environment and economy.
Sure, recycling uses extra power (hence requiring more oil/coal/gas) and will also release fumes into the air (from the power and the recycling process itself).
However, not recycling will require more mining and processing to produce more raw materials for new electronic components. Not recycling will result in computers and electronics taking up landfill space. Not recycling will add pollutants to the local ecosystems (eg lead from all solder points and reflow work, PCB's from many plastics, etc).
Which of these two scenarios is worse I cannot say, but it's not nearly as cut-and-dry as you try to make it.
Regarding reusing computers, you could still donate/sell your computer to needy people or willing consumers, just as you can do now. It's the dumping of your mobo and other cards into the trash that they're trying to reduce.
Plus, you say one can "always" find a second-hand market. What about when they're through with the product, maybe a third-hand market. But eventually nobody will want to use your screaming 10 MHz 386 box anymore. Who will recycle it then?
What exactly is the point of this new legislation if not a new way to add another hidden tax?
Well, from the article : "According to the bill, the fees would be used to fund government grants to agencies or individuals willing to recycle the used computers. A maximum of ten percent of the fees can be used for administrative costs, the bill says. The organizations have the right to recycle and/or resell the used PCs, which must be performed in accordance with [sic] in accordance with environmental health laws."
So there you have it, even you (assuming you're eligible under the program) would be able to apply for a government grant, funded by this tax, to establish reselling the used PC's. So if you're really so interested in ensuring used PC's go to second-hand markets then you should be praising this bill, not complaining about it.
Short answer : it's possible but would be, as you say, "unbearably slow".
Long answer : Your question is the fundamental reason why the field of Statistical Mechanics exists in the first place. We know the laws of physics very well at the atomic level, but all the inter-particle forces will grow exponentially. Take a picogram of water, which would encompass a sphere with 60 micron radius, of similar size to a human egg, as per your request. Such a 'small' quantity of water will contain about 100 billion atoms (3 atoms per water molecule). This would be a very simple system of only water, without complications of DNA, proteins, and other organics.
However - chemical processes are primarily governed by electron interactions (between themselves and nuclei). For simplicity, one could probably model the nucleus merely as a simple charge, ignoring individual protons and neutrons, at least to first order. But the electrons must be independent, so this would leave each water molecule with 3 nuclei and 10 electrons. So that would really be about 300 billion charged entities to model. Assuming only Coulombic interactions (charge-charge repulsion/attraction) between charge pairs, there are about 5e23 such interactions to model (all individual pairs that can be produced), just for calculating the forces to advance the system from one state to the next (ignoring summation and momentum considerations). If you had a 1 Teraflop cluster, and assuming you can do one calculation per clock cycle (very generous), it would take about 15,000 years just to make one small time evolution of the system!!!
Now account for quantum mechanics (essential in system of this size, especially for molecular electron interactions) and the extra baggage of maintaining the wavefunctions (or doing an ensemble average of wavefunction expectation values). Then add in more complexity to allow for DNA and other organics. Then do enough time evolutions to advance the system far enough to see the interactions of interest. Our sun will be long burnt out by that time.
Hell, when you take an elementary course in quantum mechanics, you see that modelling an 'ideal' hydrogen atom is doable. By ideal this means ignoring relativity, interactions between electron spin and it's orbit, interactions between electron spin and proton spin, etc etc. Add in these real factors and it becomes much harder. Although such a system you could probably make more approximations, such as assuming exponential charge screening, which means the Coulomb forces would act only in a local area. But still the processing time would be incredible.
Then when you try to model something more complicated, like Helium, it gets VERY difficult. Even the best simulations nowadays can't use too many particles for a real macroscopic system, because you need to do enough averaging to get worthwhile results, but you also cannot wait an eternity.
So that's why statistical mechanics is used, if you have a room full of air, you cannot model all the individual nitrogen and oxygen molecules bouncing off each other, but you can determine average behavior, such as pressure and temperature. And with statistical mechanics you can calculate the relative uncertainties of these quantities (ie, how much variation you'd expect in such a measure of a quantity that's defined as an average anyway), which gives it more utility than thermodynamics. But doing statistical mechanics of a very complicated system with DNA, proteins, and other organics, and accounting for quantum mechanics, would quickly become extraordinarily difficult to model and calculate as well. There would be enough individual parts there (DNA sequences, for instance) that you'd encounter the same difficulties just described.
Nice sensationalist title, but there's no interesting physics in that link.
It's easy to create signals with "phase velocities" faster than the speed of light, for example set up a series of identical oscillators such that the phase of oscillation is perfectly in sync (within a stationary observers frame). Such a system will have an infinite phase velocity, (or within the limits of experimental error it can easily be made greater than c). This phase velocity merely means the phase of the "wave" of the oscillation appears to travel infinitely fast from one oscillator to the next.
But the key point is that no information is transferred faster than the speed of light, and thus everything still adheres to the confines of special relativity.
So the parent AC is correct that one can create an effective velocity larger than c, but one cannot do anything useful with it.
I forgot to mention that the proposed NASA budget that cuts the Hubble Space Telescope was only the proposal by the White House. Congress has to vote on the actual budget, and thus has the power to include HST funding. But they will only do this if they can be shown that cutting HST is a bad idea, and that's why our feedback will be absolutely essential.
I already modded on this thread, but I'm giving up my moderation to write this very important message : If you believe in the continued operation of HST then Write to your Congressmen!!! If you have complaints about the direction the country is headed it's your civic duty (and even obligation) to give your opinion to your Congressmen. It's really simple, and after I first reluctantly did it I found myself wanting to write them more often on various issues. They (really one of their staff) will eventually write you back about the issue, and it really makes you feel worthwhile to be part of the system.
Click here to get to the homepages of both of your senators, and urge them to continue funding HST. Similarly, click here to contact your representative in the House. Make sure in your writeup to include your name and address. It is good to send them an email or use the contact webform box, but even better to send an actual letter via USPS.
I can't stress this enough. Congressmen usually listen to their constituents, but typically most of their feedback comes from well-funded lobby groups that can afford to contact them on every relevent piece of legislation. If enough of us can demonstrate to them how important Hubble is to the scientific research and legacy of the US, we can actually make a positive impact.
Here is a page with some extra information about writing your Congressmen. Please do this (right now even). The 10 minutes you spend contacting them can be repaid tenfold if your message influences their decision!
If you have that kind of money, why are you spending it sitting in the middle of downtown instead of sitting on a beach somewhere.
There are two somewhat conflicting thoughts I've got. The first is that the guy is a crazed fanboy creepy (ie, stalker-like) loser, perhaps in awe of anything starwars, perhaps just taking the last chance to wait in line for what was the legendary fictional story from his childhood days (he was 3 when #4 came out). Okay, he obviously wants to see the movie on opening night. Assuming he could work a job making minimum wage ($7.35 in Washington), if he worked 8 hours each of the 139 days he waited in line (yeah, no weekends there, but he has no weekends now) he'd have a bit over $8000. Assuming he could find a small shitbox to rent for $500 a month and would spend another $500 a month on food + utilities, he'd still have over $3000 by the time the movie came out. With that cash he'd probably be able to rent an entire theater (or great portion thereof) and have one hell of a party on opening night.
But then in the article I saw this bit :
He knows, from past experience, that in a few months, he will begin receiving 600 to 700 e-mails, and do seven to 10 radio interviews a day. Already, the interview calls start at 3:30 a.m., and he has appeared on the "Jimmy Kimmel Live" show on ABC.
That reveals his true ulterior motive, and it's pretty clever. PUBLICITY!!! Several weeks ago barely anybody knew who this guy was, but now he's getting more infamous each day (in certain circles at least), and I carefully use the word infamous instead of famous. People now know who he is. Maybe not by name, maybe not by face. But - he can now go to any agent's office (either TV, music, etc) and say he's the guy that's been camping out for Episode III for 139 days straight. Bam, instant publicity, which means $$$$$ to any agent.
It's just like those notoriously bad singers on American Idol that were obviously chosen for humor factor with zero chance of surviving the first round. One of these guys went on to make an album and even went on a small tour, because he was known as that horrendously awful singer from Idol. He's brilliant, he built a fan base, maybe he'll go on to appear in movies or something else, and has a great foothold into the entertainment industry.
Our Sith-waiting friend is most likely doing the same thing.
Off topic, but I recently saw a bumper sticker that said "Capital Punishment - WWJD?". I bet a number of religious Republicans don't want to go there, but raise enough awareness and people might realize the un-Christian actions of the republican party (eg Bush's term in Texas w/ high rate of execution).
For example, given the seemingly paradoxical relationship between Christians and Republicans, I would love to see the following bumper stickers:
"Attack Iraq? WWJD?"
"Abu Ghraib? WWJD?"
"Human Rights Violations at Guantanamo? WWJD?"
"Environmentally-irresponsible SUV's? WWJD?"
etc etc. Then again, I'm sure Karl Rove would be able to find some New Testament quote that, taken to the letter instead of the spirit, would seemingly support each of these activities.
Contrary to popular belief, the Christian view has always been, "Look at the evidence."
Okay, I've been to a few church services (Catholic, Gospel, several other Protestant sects), but I've not encountered this view. Can you show in the Bible, the associated liturgy, or transcripts of well-known prechers/ministers where one is urged to challenge conventional views (as in the Eastern religions I mentioned previously)? Or specifically where the lack of evidence (sorry, a missing body does not by itself indicate resurrection) of the Resurrection, Heaven, Hell, Satan, etc imply that these components of Christianity aren't that important to it's overall practice? Or better yet, where accepting Jesus isn't as important as helping someone more needy?
I'm not trying to denigrate you nor criticize Christianity, it's just that all of my experiences at Christian ceremonies and services focused primarily on faith and had very little to do with experience. So I am curious to know about this. I'll admit I've perhaps only been to 15 church services total, so that's a relatively small sample size. In my experiences so far, most of these services involved three basic tenets, all with a common reward or punishment - Accept Jesus, avoid sin, and practice righteousness of character. Adherence to these goals (with absolutely no evidence that is shown) will reward the good Christian soul with Heaven, failure to do these will send him/her to hell. The reward of heaven by accepting Jesus is the concept most often mentioned, seeming to permeate everything (in my experiences anyway). And quite often (most notably on the TV bible personalities) versus are quoted directly from the bible and presented as fact, or as the absolute authority on which to base your actions.
I don't see how blindly accepting Jesus and Heaven or Hell has anything to do with experience and proof, but only as blind faith. I've never seen a preacher/minister or religious Christian question whether Heaven/Hell exists or whether Jesus was really the Son of God. Neither on top of that have I seen the encouragement of challenging conventionally-established views. Once again, I'm not criticizing any of these sects of Christianity, but in my experiences so far they have not demonstrated to me any sense of experience, but instead base almost everything on faith.
I'm sure there are churches or other branches where being a "Good Christian" and helping others is more important than accepting Jesus and going to heaven, and where they discuss complicated situations and how to best deal with them (with no persuasion of heaven/hell by choosing the right path), etc. But I've not encountered any of these yet.
How about this theory then, could it possibly make both camps happy? (Well, it does mention God, that could always be changed to Creator, whereby that could mean God, Big Bang, or whatever to each student)
When God created the Universe, (s)he designed the genetic structure of the lowest forms of life (which were created before man) with the ability to reproduce their genetic code asexually, occasionally making errors that caused species variety, until sexual reproduction was achieved at which point variation was substantially increased. Through natural selection, God's will was carried out as the plants and animals evolved, and ultimately the line of primates formed, which eventually produced Man.
That way you can explain nearly anything to satisfy religion/science.
That's why I don't get the whole animosity of the Church toward the Heliocentric theory in the middle ages. There was no mention (that I know of anyway) of Geocentric theory in the bible. Why couldn't they say God specifically created the sun at the center of the universe. God specifically designed atoms such that they would form molecules to have the noted properties that they have, which allow for evolution. Or more generally - this effect happens because it is God's will.
You bring up a VERY good point. Why, of the subset of all scientific theories do they focus on evolution, and not much else? Take for example the inverse square force between two charges. It's taught in schools as fact that F~(r^-2), but only in graduate study of E&M (Jackson) was it mentioned that the best experiments (which people occasionally re-do when they have sensors that can improve on the results) have only limited it to something like r^(-n) where n=2.0000000+/- 0.0000003 (I'm making up these numbers, but IIRC they're not that far off).
Religion demands adherence without proof. Science demands adherence only with proof.
Not universally. Western religions tend to demand adherence without proof (leaps of faith and such), but Eastern religions (and some Jewish mysticism) tend to be more philosophical and introspective. For example, in Zen Buddhism blindly adhering to written or taught dogma is typically shunned. Instead, the wealth of religious texts in these zen sects are to be taken merely as a "finger pointing to the moon". If you spend too much time looking at the finger, you'll lose sight of the moon.
Wow, that IEEE link one was one of the most informative links I've come across on slashdot, pretty illuminating. It's amazing that the communication system wasn't fully tested. Here's a few quotes for those too lazy to read the article (a bit long) about the problem that a Swedish ESA
engineer caught, while everybody else (NASA + ESA) didn't want to consider it.
It's a real shame that the private Italian subcontractor didn't allow transparency in the plans for the transmitter. I mean, this is a SCIENCE mission, not a competition for profits. (The company viewed NASA as their competitor, and the transmitter as proprietary).
The board discovered that Alenia Spazio SpA, the Rome-based company that built the radio link, had properly anticipated the need to make the receiver sensitive over a wide enough range of frequencies to detect Huygens's carrier signal even when Doppler shifted. But it had overlooked another subtle consequence: Doppler shift would affect not just the frequency of the carrier wave that the probe's vital observations would be transmitted on but also the digitally encoded signal itself. In effect, the shift would push the signal out of synch with the timing scheme used to recover data from the phase-modulated carrier.
Because of Doppler shift, the frequency at which bits would be arriving from Huygens would be significantly different from the nominal data rate of 8192 bits per second. As the radio wave from the lander was compressed by Doppler shift, the data rate would increase as the length of each bit was reduced.
Although the receiver's decoder could accommodate small shifts in the received data rate, it was completely out of its league here. The incoming signal was doomed to be chopped up into chunks that didn't correspond to the actual data being sent, and as a result the signal decoder would produce a stream of binary junk. The situation would be like trying to watch a scrambled TV channel--the TV's tuned in fine, but you still can't make out the picture.
Alenia Spazio wasn't alone in missing the impact Doppler shift would have on the decoder. All the design reviews of the communications link, including those conducted with NASA participation, also failed to notice the error that would threaten to turn Huygens's moment of glory into an embarrassing failure.
Alenia Spazio's insistence on confidentiality may have played a role in this oversight. NASA reviewers were never given the specs of the receiver. As JPL's Mitchell explained to Spectrum, "Alenia Spazio considered JPL to be a competitor and treated the radio design as proprietary data."
JPL's Horttor admitted that NASA probably could have insisted on seeing the design if it had agreed to sign standard nondisclosure agreements, but NASA didn't consider the effort worthwhile, automatically assuming Alenia Spazio would compensate for the changing data rate.
Slashdot Mirror
Self-assembled systems can feasibly be very small (several atoms), a la DNA (a natural self-assembling system). Lithographic systems (electron beam or optical) are limited by diffraction of the corresponding electrons or photons used to expose the photoresist, as well as the surface properties of the photoresist itself. For these methods the minimum feature size producable can be of order 10 nm for e-beam lithography, and 100 to 1000 nm for optical lithography, depending on wavelength. Self-assembled systems could possibly be as small as order 1 nm in size.
First a note - All of my experience with quantum dots is at cryogenic temperatures, eg 4.2K and below, so I'm not aware of the behavior of systems at higher temperatures.
It sounds like this author is making very generalized hand-waving explanations about these fairly complex systems. And is vague enough so that if any effect is discovered, he'll claim that he "discovered" it first. But if he did claim that, it would be somewhat disingenuous because it's very difficult to predict what kind of coherent long-range many-body "emergent" patterns would manifest themselves. Ie, the low-level physics is hard, the fabrication is hard, determining large-scale effects is hard, etc. Heck, even describing a simple helium-atom is hard enough (the quantum-mechanical 3-body problem), with three interacting coulomb forces to work with in addition to the nuclear potential. So it sounds like he's handwaving, but in an attempt to claim prediction of any future discovery based on quantum-dots.
On a side note, though, all matter is already programmable by default. Phase transitions, for example, will happen at specific temperatures, or magnetic fields, etc, such that the macroscopic behavior of the material can be 'programmed' by pushing through the phase transition.
That pretty much is what researchers in quantum computing are trying to do, it's a whole different ballgame. For example, In classical computing, 3 bits lets you put a system into exactly one of 8 (2^3) distinct states. However a quantum computer with 3 qubits will let you put the system into a superposition of these eight states, such that the superpositiong (ie, wavefunction) is properly normalized.
Quantum mechanics works in a whole different mathematical basis (Hilbert Space or Fock Space). The algebras of these spaces is quite different from classical computing, so yes, it's going to be a whole new way of looking at computing, at least at the lowest level.
On a side note, it sounds like you have just read some Thomas Kuhn, as per your frequent usage of 'paradigm', along with comparing 'evolution' to 'revolution'.
But hey, I was fiddling with a He3 fridge as you wrote that, so I had to give at least some response!
I don't really understand what you're asking, but I gave a semi tongue-in-cheek response to the parent poster (probably not too noticeable). Meaning that I only argued against the fact that He3 has no use on Earth, but of course not implying it would be efficient to mine He3 on the moon.
Interesting comment, I use He3 (in closed systems) almost every day in my lab. He4 liquefies at 4.2K, but that's a bit too toasty for probing certain quantum coherence interactions and quantum phase transitions. A liter of liquid He4 costs about $4 (liquid nitrogen, at 77K, is cheaper than milk). But a gaseous liter of He3 is several hundred dollars.
We've got a sorption-pumped He3 refrigeration system that uses a closed-cycle He3 unit for evaporative cooling, and the whole things sits in a dewar of He4 at 4.2K. Can get to temperatures of about 250 mK.
When we need to go colder we employ a dilution refridgerator, which uses a carefully-tuned mixture of He3/He4, and can create a phase separation between a dilute and condensed mixture of the two helium isotopes. By crossing the phase boundary from the condensed to dilute phase, one can absorb heat from a sample (very similar to standard air conditioner cycling). We can get down to about 10 mK with this system, but it'll take you all day and lots of prep work to just to load and cool one sample.
So yeah, the cryogenics community would love getting more He3. It's really rare here on Earth, but it would be really cool to have more of this stuff. I don't know what other industries would make use of it, but it would probably find other useful applications.
You've got the most limited worldview of scientific research I've ever encountered. Theoretical research is done all the time to further our knowledge. What kind of scientific research do you do that gives you authority to make this comment?
Many times the end results cannot be determined to have any practical usefulness, but it builds on the world body of knowledge that can be eventually used. For example, think of the first researchers studying band structure of doped silicon. Sounds pretty boring, but it's the cornerstone for the entire microelectronics industry. It took scientists with clever insight to be able to apply this research to make PN junctions, and then transistors.
But where does this mean they will carry it forward? For example, various biologists study complex predator-prey relations, and can determine situations where the tigers kill all the gazelles on the land very quickly, extincting first the gazelles and then themselves. Do you actually think they then seek funding to try to instantiate this model? If it was something smaller-scale, such as two bacteria species in a jar, then perhaps a researcher would try to verify the model. But they don't do it just to get funding, as you say.
Responsible climatologists are putting their time and effort into helping to understand the mess we're making on Earth, before spreading it to Mars.
First of all she's a planetary scientist, and an undergrad student to boot. Secondly, this climactic study was most likely spun off from similar research on PFC's or other fluorocarbons here on Earth. Thirdly, whatever results they get from this study have a decent probability of adding to the body of knowledge for Earth-based climatologists studying various global warming scenarios.
For example, one difference between Earth and Mars warming is that Earth has a much larger ozone layer, which is affected by CFCs. That's why PFC's are looked at in the Martian study instead, and also they're looking at possible methods that might create a larger Martian ozone layer. Such research could help terrestrial scientists if it's determined that our ozone layer needs to be repaired.
What are you talking about? Can you point to any links that document real PROPOSALS by "NASA scienticians" to actually warm Mars (as opposed to mere studies and models)? Or are you knee-jerking based on the misleading slashdot summary that implies there really is such a proposal?
It's ironic that you want to belittle "NASA scienticians" for arriving at premature conclusions, when you yourself have done the exact same thing by not even spending 30 seconds to click on a link and read the article.
If you actually read the article, and not just the misleading sensationalist slashdot blurb, you'd see this is not a PROPOSAL to heat Mars. It's a STUDY to look at various options that COULD be used to terraform Mars, and how to get past various other problems that would crop up (for example relying exlusively on CO2 for the warming process).
And either way, these studies are either spinoffs of, or will contribute to, studies of Earth-based global warming, and can help provide useful data and methods for understanding these problems close to home.
Did you at least read the article? The slashdot writeup was sensationally misleading, as usual. Actually, here's some more info on the project, more than is in the Guardian link.
Basically, it is NOT a proposal to warm Mars, it's a study exploring various ways that Mars COULD be heated, and how long such methods would take (conducted by an undergrad student at U. Mass). And they even acknowledge in that link that it would be significantly well into the future before any decision would every be implemented to try warming Mars, and at that point the method of using PFC's would probably be archaic compared to future technology.
So keep your pantyhose on, NASA isn't trying to warm Mars, it's just a study. And in all likelihood it was an offshoot of various studies of global warming on Earth, in which case doing more planetary models of effects of PFCs, among others, would be a good thing!
You mean, NASA, who's bureaucratic administrators pushed for the launch (with I believe governmental pressure), against the objection of the engineers familiar with the system that failed. Don't dis all of NASA's engineering abilities and accomplishments because of PHB's and politicians.
NASA, whose craft break up on re-entry just because they got smacked with some foam?
Your statement here is so deceiving, I really hope you don't believe it yourself. It wasn't foam that broke up the craft, it was the friction heating on re-entry. And that happened because the heat shield was damaged by a piece of 'foam', but the foam didn't directly break up the shuttle.
But thanks, because your example proves the point of the poster. Shit happens, and NASA has many redundancies to deal with said shit happening. Spacecraft are far more complex than mere cars, so in space shit happens greatly. You need to be far more familiar with aerodynamics, materials stress and thermal properties, reactive propulsion, than the standard automobile hacker needs to be.
What evidence do you have that NASA is better at this than anybody else?
They're not necessarily, but I think the poster meant Aerospace professionals, not just Joe Hacker Schmoe who can soup up his Honda Civic. For example, much rocketry and other components come from Boeing and Lockheed-Martin, among other subcontractors.
But there's SO MUCH MORE that can go wrong with space systems, as opposed to autos, and when stuff goes wrong in space it tends to go REALLY wrong. Eg, an out of control car can steer towards some bushes to slow down, but an out of control orbiter during re-entry is pretty fucked.
Of course the software matters, what doesn't matter is that the software is 20 years old (as long as it processes/transmits data fast enough, which it does). Bugs are bugs, but age in itself doesn't make software bad. In fact, one could claim that older software has had more exposure time, allowing the identification and debugging of more mission-critical bugs.
BTW, my girlfriend works at STScI, so I know a few things about HST ;-)
WFC3 and COS are still on the ground, hopefully to make it to Hubble on either a manned or robotic mission. Here's a list of past, present, and future Hubble instruments, along with links to their homepages with all the technical information you could want.
Hubble is nowhere near state of the art (some software in it is 25-30 yrs old) but it works and has exceeded the wildest expectations of it's builders. Kind of a Brooklyn Bridge in space, the first one built but still works great and setting a high standard.
The software doesn't matter, it's the front-end detectors that limit the accuracy on the acquired data. Once it's properly digitized, the software will only limit the speed it can be transmitted back to Earth. But even that speed is dwarfed by the long integration times Hubble acquires for very faint objects.
The accessibity of Hubble is what contributed to it's success. Sensor technology is a continuing evolving field, and the ability to periodically put better, more sensitive detectors onto Hubble has contributed to it remaining one of the most competitive telescopes available. When James Webb telescope is launched, it won't be upgradeable, which means it won't be able to take advantage of the great advances in sensor technology we'll probably have in the next 20 years.
Okay, I'll bite. Did you read the article, or are you just knee-jerking?
You've listed one or two problems with recycling, but haven't identified related problems with NOT recycling, nor have you considered of the appropriate scenarios which approach would have the most beneficial impact on the environment and economy. Sure, recycling uses extra power (hence requiring more oil/coal/gas) and will also release fumes into the air (from the power and the recycling process itself).
However, not recycling will require more mining and processing to produce more raw materials for new electronic components. Not recycling will result in computers and electronics taking up landfill space. Not recycling will add pollutants to the local ecosystems (eg lead from all solder points and reflow work, PCB's from many plastics, etc).
Which of these two scenarios is worse I cannot say, but it's not nearly as cut-and-dry as you try to make it.
Regarding reusing computers, you could still donate/sell your computer to needy people or willing consumers, just as you can do now. It's the dumping of your mobo and other cards into the trash that they're trying to reduce.
Plus, you say one can "always" find a second-hand market. What about when they're through with the product, maybe a third-hand market. But eventually nobody will want to use your screaming 10 MHz 386 box anymore. Who will recycle it then?
What exactly is the point of this new legislation if not a new way to add another hidden tax?
Well, from the article : "According to the bill, the fees would be used to fund government grants to agencies or individuals willing to recycle the used computers. A maximum of ten percent of the fees can be used for administrative costs, the bill says. The organizations have the right to recycle and/or resell the used PCs, which must be performed in accordance with [sic] in accordance with environmental health laws."
So there you have it, even you (assuming you're eligible under the program) would be able to apply for a government grant, funded by this tax, to establish reselling the used PC's. So if you're really so interested in ensuring used PC's go to second-hand markets then you should be praising this bill, not complaining about it.
Long answer : Your question is the fundamental reason why the field of Statistical Mechanics exists in the first place. We know the laws of physics very well at the atomic level, but all the inter-particle forces will grow exponentially. Take a picogram of water, which would encompass a sphere with 60 micron radius, of similar size to a human egg, as per your request. Such a 'small' quantity of water will contain about 100 billion atoms (3 atoms per water molecule). This would be a very simple system of only water, without complications of DNA, proteins, and other organics.
However - chemical processes are primarily governed by electron interactions (between themselves and nuclei). For simplicity, one could probably model the nucleus merely as a simple charge, ignoring individual protons and neutrons, at least to first order. But the electrons must be independent, so this would leave each water molecule with 3 nuclei and 10 electrons. So that would really be about 300 billion charged entities to model. Assuming only Coulombic interactions (charge-charge repulsion/attraction) between charge pairs, there are about 5e23 such interactions to model (all individual pairs that can be produced), just for calculating the forces to advance the system from one state to the next (ignoring summation and momentum considerations). If you had a 1 Teraflop cluster, and assuming you can do one calculation per clock cycle (very generous), it would take about 15,000 years just to make one small time evolution of the system!!!
Now account for quantum mechanics (essential in system of this size, especially for molecular electron interactions) and the extra baggage of maintaining the wavefunctions (or doing an ensemble average of wavefunction expectation values). Then add in more complexity to allow for DNA and other organics. Then do enough time evolutions to advance the system far enough to see the interactions of interest. Our sun will be long burnt out by that time.
Hell, when you take an elementary course in quantum mechanics, you see that modelling an 'ideal' hydrogen atom is doable. By ideal this means ignoring relativity, interactions between electron spin and it's orbit, interactions between electron spin and proton spin, etc etc. Add in these real factors and it becomes much harder. Although such a system you could probably make more approximations, such as assuming exponential charge screening, which means the Coulomb forces would act only in a local area. But still the processing time would be incredible.
Then when you try to model something more complicated, like Helium, it gets VERY difficult. Even the best simulations nowadays can't use too many particles for a real macroscopic system, because you need to do enough averaging to get worthwhile results, but you also cannot wait an eternity.
So that's why statistical mechanics is used, if you have a room full of air, you cannot model all the individual nitrogen and oxygen molecules bouncing off each other, but you can determine average behavior, such as pressure and temperature. And with statistical mechanics you can calculate the relative uncertainties of these quantities (ie, how much variation you'd expect in such a measure of a quantity that's defined as an average anyway), which gives it more utility than thermodynamics. But doing statistical mechanics of a very complicated system with DNA, proteins, and other organics, and accounting for quantum mechanics, would quickly become extraordinarily difficult to model and calculate as well. There would be enough individual parts there (DNA sequences, for instance) that you'd encounter the same difficulties just described.
It's easy to create signals with "phase velocities" faster than the speed of light, for example set up a series of identical oscillators such that the phase of oscillation is perfectly in sync (within a stationary observers frame). Such a system will have an infinite phase velocity, (or within the limits of experimental error it can easily be made greater than c). This phase velocity merely means the phase of the "wave" of the oscillation appears to travel infinitely fast from one oscillator to the next.
But the key point is that no information is transferred faster than the speed of light, and thus everything still adheres to the confines of special relativity. So the parent AC is correct that one can create an effective velocity larger than c, but one cannot do anything useful with it.
I forgot to mention that the proposed NASA budget that cuts the Hubble Space Telescope was only the proposal by the White House. Congress has to vote on the actual budget, and thus has the power to include HST funding. But they will only do this if they can be shown that cutting HST is a bad idea, and that's why our feedback will be absolutely essential.
Click here to get to the homepages of both of your senators, and urge them to continue funding HST. Similarly, click here to contact your representative in the House. Make sure in your writeup to include your name and address. It is good to send them an email or use the contact webform box, but even better to send an actual letter via USPS.
I can't stress this enough. Congressmen usually listen to their constituents, but typically most of their feedback comes from well-funded lobby groups that can afford to contact them on every relevent piece of legislation. If enough of us can demonstrate to them how important Hubble is to the scientific research and legacy of the US, we can actually make a positive impact.
Here is a page with some extra information about writing your Congressmen. Please do this (right now even). The 10 minutes you spend contacting them can be repaid tenfold if your message influences their decision!
There are two somewhat conflicting thoughts I've got. The first is that the guy is a crazed fanboy creepy (ie, stalker-like) loser, perhaps in awe of anything starwars, perhaps just taking the last chance to wait in line for what was the legendary fictional story from his childhood days (he was 3 when #4 came out). Okay, he obviously wants to see the movie on opening night. Assuming he could work a job making minimum wage ($7.35 in Washington), if he worked 8 hours each of the 139 days he waited in line (yeah, no weekends there, but he has no weekends now) he'd have a bit over $8000. Assuming he could find a small shitbox to rent for $500 a month and would spend another $500 a month on food + utilities, he'd still have over $3000 by the time the movie came out. With that cash he'd probably be able to rent an entire theater (or great portion thereof) and have one hell of a party on opening night.
But then in the article I saw this bit :
He knows, from past experience, that in a few months, he will begin receiving 600 to 700 e-mails, and do seven to 10 radio interviews a day. Already, the interview calls start at 3:30 a.m., and he has appeared on the "Jimmy Kimmel Live" show on ABC.
That reveals his true ulterior motive, and it's pretty clever. PUBLICITY!!! Several weeks ago barely anybody knew who this guy was, but now he's getting more infamous each day (in certain circles at least), and I carefully use the word infamous instead of famous. People now know who he is. Maybe not by name, maybe not by face. But - he can now go to any agent's office (either TV, music, etc) and say he's the guy that's been camping out for Episode III for 139 days straight. Bam, instant publicity, which means $$$$$ to any agent.
It's just like those notoriously bad singers on American Idol that were obviously chosen for humor factor with zero chance of surviving the first round. One of these guys went on to make an album and even went on a small tour, because he was known as that horrendously awful singer from Idol. He's brilliant, he built a fan base, maybe he'll go on to appear in movies or something else, and has a great foothold into the entertainment industry.
Our Sith-waiting friend is most likely doing the same thing.
For example, given the seemingly paradoxical relationship between Christians and Republicans, I would love to see the following bumper stickers:
- "Attack Iraq? WWJD?"
- "Abu Ghraib? WWJD?"
- "Human Rights Violations at Guantanamo? WWJD?"
- "Environmentally-irresponsible SUV's? WWJD?"
etc etc. Then again, I'm sure Karl Rove would be able to find some New Testament quote that, taken to the letter instead of the spirit, would seemingly support each of these activities.Okay, I've been to a few church services (Catholic, Gospel, several other Protestant sects), but I've not encountered this view. Can you show in the Bible, the associated liturgy, or transcripts of well-known prechers/ministers where one is urged to challenge conventional views (as in the Eastern religions I mentioned previously)? Or specifically where the lack of evidence (sorry, a missing body does not by itself indicate resurrection) of the Resurrection, Heaven, Hell, Satan, etc imply that these components of Christianity aren't that important to it's overall practice? Or better yet, where accepting Jesus isn't as important as helping someone more needy?
I'm not trying to denigrate you nor criticize Christianity, it's just that all of my experiences at Christian ceremonies and services focused primarily on faith and had very little to do with experience. So I am curious to know about this. I'll admit I've perhaps only been to 15 church services total, so that's a relatively small sample size. In my experiences so far, most of these services involved three basic tenets, all with a common reward or punishment - Accept Jesus, avoid sin, and practice righteousness of character. Adherence to these goals (with absolutely no evidence that is shown) will reward the good Christian soul with Heaven, failure to do these will send him/her to hell. The reward of heaven by accepting Jesus is the concept most often mentioned, seeming to permeate everything (in my experiences anyway). And quite often (most notably on the TV bible personalities) versus are quoted directly from the bible and presented as fact, or as the absolute authority on which to base your actions.
I don't see how blindly accepting Jesus and Heaven or Hell has anything to do with experience and proof, but only as blind faith. I've never seen a preacher/minister or religious Christian question whether Heaven/Hell exists or whether Jesus was really the Son of God. Neither on top of that have I seen the encouragement of challenging conventionally-established views. Once again, I'm not criticizing any of these sects of Christianity, but in my experiences so far they have not demonstrated to me any sense of experience, but instead base almost everything on faith.
I'm sure there are churches or other branches where being a "Good Christian" and helping others is more important than accepting Jesus and going to heaven, and where they discuss complicated situations and how to best deal with them (with no persuasion of heaven/hell by choosing the right path), etc. But I've not encountered any of these yet.
When God created the Universe, (s)he designed the genetic structure of the lowest forms of life (which were created before man) with the ability to reproduce their genetic code asexually, occasionally making errors that caused species variety, until sexual reproduction was achieved at which point variation was substantially increased. Through natural selection, God's will was carried out as the plants and animals evolved, and ultimately the line of primates formed, which eventually produced Man.
That way you can explain nearly anything to satisfy religion/science.
That's why I don't get the whole animosity of the Church toward the Heliocentric theory in the middle ages. There was no mention (that I know of anyway) of Geocentric theory in the bible. Why couldn't they say God specifically created the sun at the center of the universe. God specifically designed atoms such that they would form molecules to have the noted properties that they have, which allow for evolution. Or more generally - this effect happens because it is God's will.
You bring up a VERY good point. Why, of the subset of all scientific theories do they focus on evolution, and not much else? Take for example the inverse square force between two charges. It's taught in schools as fact that F~(r^-2), but only in graduate study of E&M (Jackson) was it mentioned that the best experiments (which people occasionally re-do when they have sensors that can improve on the results) have only limited it to something like r^(-n) where n=2.0000000+/- 0.0000003 (I'm making up these numbers, but IIRC they're not that far off).
Not universally. Western religions tend to demand adherence without proof (leaps of faith and such), but Eastern religions (and some Jewish mysticism) tend to be more philosophical and introspective. For example, in Zen Buddhism blindly adhering to written or taught dogma is typically shunned. Instead, the wealth of religious texts in these zen sects are to be taken merely as a "finger pointing to the moon". If you spend too much time looking at the finger, you'll lose sight of the moon.
It's a real shame that the private Italian subcontractor didn't allow transparency in the plans for the transmitter. I mean, this is a SCIENCE mission, not a competition for profits. (The company viewed NASA as their competitor, and the transmitter as proprietary).
The board discovered that Alenia Spazio SpA, the Rome-based company that built the radio link, had properly anticipated the need to make the receiver sensitive over a wide enough range of frequencies to detect Huygens's carrier signal even when Doppler shifted. But it had overlooked another subtle consequence: Doppler shift would affect not just the frequency of the carrier wave that the probe's vital observations would be transmitted on but also the digitally encoded signal itself. In effect, the shift would push the signal out of synch with the timing scheme used to recover data from the phase-modulated carrier.
Because of Doppler shift, the frequency at which bits would be arriving from Huygens would be significantly different from the nominal data rate of 8192 bits per second. As the radio wave from the lander was compressed by Doppler shift, the data rate would increase as the length of each bit was reduced.
Although the receiver's decoder could accommodate small shifts in the received data rate, it was completely out of its league here. The incoming signal was doomed to be chopped up into chunks that didn't correspond to the actual data being sent, and as a result the signal decoder would produce a stream of binary junk. The situation would be like trying to watch a scrambled TV channel--the TV's tuned in fine, but you still can't make out the picture.
Alenia Spazio wasn't alone in missing the impact Doppler shift would have on the decoder. All the design reviews of the communications link, including those conducted with NASA participation, also failed to notice the error that would threaten to turn Huygens's moment of glory into an embarrassing failure.
Alenia Spazio's insistence on confidentiality may have played a role in this oversight. NASA reviewers were never given the specs of the receiver. As JPL's Mitchell explained to Spectrum, "Alenia Spazio considered JPL to be a competitor and treated the radio design as proprietary data."
JPL's Horttor admitted that NASA probably could have insisted on seeing the design if it had agreed to sign standard nondisclosure agreements, but NASA didn't consider the effort worthwhile, automatically assuming Alenia Spazio would compensate for the changing data rate.